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13.1.2
Refrigerant replacement procedure with unit running (refrigerant charge in the vapour
phase)
Caution: charge vapour only. Do not charge liquid because it may damage the compressor.
Connect the refrigerant cylinder to the service valve without tightening the coupling. Drain the
connection piping and tighten the coupling. Charge the circuit until the indicator indicates liquid
without bubbles. Now the unit has the required charge. Make sure to not over-charge the circuit.
Charging more than necessary leads to a higher delivery pressure, greater power consumption
and possible damage to the compressor.
The symptoms of a low refrigerant charge are:
o Low evaporation pressure
o High value of superheating
o Low value of sub-cooling
In this case, add refrigerant R410A. The system is provided with a charging port between the
expansion valve and the evaporator. Charge refrigerant until conditions return to work normal.
Remember to replace the cap closing the valve at the end.
IMPORTANT
If the unit has not been provided with integrated pump on board, do not turn off the external pump
before 3 minutes have elapsed after turning off the last compressor. The early shutdown of the
pump causes a water flow alarm failure.
Figure 22
Refrigerant charge in the vapour
phase
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